Radio-transmitter



C. L. FARRAND.

RADIO TRANSMITTER.

APPLICATION FILED 1u11E14, 1919.

A1,385,81 8. aented July 269 1921,.

2 SHEETS-SHEET 2.

nutren sTA'rjss Fureur ortica..

CLAIR L, FARRAND, F ELIZABETH, NEW JERSEY, ASSGNOR, BY MESNE Aitt'ill MENTS, TO RADIO CORPORATION OF AMB/ICA, te

WARE.

CItlE'ORATI-ON Ulli DEXIA;

Z RADIO-:TRANSMITTER i.aeasie.

Application tiled .Tune 14,

To alt 'whom z' may concern.'

Be it known l'that l, CLAIR L. FARRAND, a citizen of thel United States, and a resident of Elizabeth, county of Union, State of New Jersey. have invented certain new and useful .improvements in Radio-'l`ransmitters, of' .which the following, is a specilicatmn accompanied by drawings.v

This invention relates to improvements in radio transmitters, employing a vacuum tube or tubes and oscillatingrircuits as the source of oscillations.

The primary object ofthe invention is to enable the maximum total electron emission of the iilament to be utilized at all times, particularly 1n radio transmission, resulting in an increase in ratio of output to filament energy, and thereby increasing the efliciency of the tube. This increasel in emciency is especially advantageous and is a decided advantage in high power vacuum tubes inv which the iilament energy is appreciable.

The invention is applicable to several types of valves or vacuum tubes, as for instance the 1l/'eagant type having the heated filament and a plurality of cold elements or plates inside the tube, and a plurality ot" shields or influencino members outside the tube: or ese the in uencingr members may lhe in the usual form of internal grids..

The invention is illustrated in the accompanying drawings, in which, t

Figure l. is adlagrammatic representation oi' circuits and lapparatus for carrying out the invention in connection with a Weagant shield valve; w Fig'. 2 illustrates graphically the electron current in an oscillating valve as normally used;

Fig. 3 illustrates graphically ,the mani-fl mum filament emission asl obtained in accordance with my invention; and

Fig. 4- is a diagrammatic view similar to diie.l l showingr avalve having all the elements 'inside the tube.

Referring to the drawings and at first more particularly to Fig. l, the transmittingu antenna A is provided with the usual variable inductance B, and is connected to ground at C. A transmitter key may be provided .in any suitable location, as at D.

The oscillating-vacuum valve E in this instance,4 comprises the evacuated tube .F containing the heated filament G and the two cold plates H, While the influencing Specification of Letters Patent.

Patented July 26, QL 191e. sei-iai im. suesse.

membersare in the form of external shields and J preferably surrounding the tube as indlcated. The filament (i is energized by the usual battery K. Y

. ln this instance a connection 'is made from a! point adjacent the filament ybattery to' a suitable. point L on in'ductance coil B, .anc

the source of plate current shown as `a generator O, isv conveniently connected between tl1e filament and the plates H .through the radio `frequency supply choke coiis P. Bypath condensers Q are connected as shown between points on the plate circuits and. the taps R on inductance B, and permit the oscillatingr currents to loiv from the oscillator through that portion of 'the inductance B indicated by the position ot the taps.

TheI shields or iniiuencinuniembers J and J are connected rcspectivei; through the adjustable taps S and ,Si to points on inductance B at which the potentiais xviii be substantially out of phase, preferably 180.out ol phase for maximum efficiency.

in explainingv the operation ot the device, reference will be had to the ,graphic curves shown in Figs. 2- yand 3. In Fior. 2 the curve il graphically represents the electron cur-- rent ina threeelement oscillating valve as I normally used, that is with a heated filament, a cold plate and an iniiuencingr menibcr or zgrid. lt is apparent in such case that the filament must be supplied with suihcient energy to emit at all times electronssuliicient to supply the maximum of current. s

Fig; 3 illustrates graphicaily the maxi mum filament emission as obtained in accordance with my invention.. The curve 'i7 represents the electron current through onel plate li as infiuenced 'by the shield il" for grid .l2 Fig. It), and 'the curve W repre# sents the electron currenttlirough the-other plate H as infiuenred by the shieid J for grid J3 Fig. It). lllhc two current curves as shown are 'i800 out ot' phase, and their sum mation is indicated approximately by the straight line X, corresponding to the maximum emission of the filament. By means of the circuits and connections illustrated, Lam enabled to so increase the ratio of output to' filament energy, that l.' 'obtain at all times' tot substantially the maximum totei electron y mici oherwise 'dw circuit-s ae 'tim sume and me device operates in the same manner de Scl'ibed, excspt that Sources of negative putentiui in the form of battrias T are shown in nii-cuit with the griis.

claim and desire to obtain by Letter;-; Ytent the fnlowing:

iin radio transmitiiig apparatus, the combination of n, vacuum valve having a iiated izahoie, il pimuliiy of com iemoiits of pintas, i1 )hu'ality of pinta cii'ciiis :Jud connecions m cmisizig Suid vacuum 'u1u/a1 generate oscillations in the pinto, circuits, an antenna, an induciuwe wil comicctedjn th@ antenna und plate, @i1-cum und a. pi ziiity of infueucing members connected to points on saif'. indi-Lemme cuil :it wvhicn the: potentas am substantiuiiy out ofvpims.

En moli@ transmitting appaz'i'it-us, the

vombinaion of a, vzu'uum viv i'iaving a 'heated vathode, :L pluiraiity ofold. elements m" pintas, a piurality of plata circuis and connections :for causing said vacuum valve to gemeint@ oscillations in the pluie' circuits, im antenna, :m induciancejcoii connected in thi :mtemm and plate circuits :und a plurality (if iii'iuencing members Connected to 'ifiius on said inductkance coii at which bhepvtntiuis am subsmntiaily SOC' out of phase, v

lIn testimony whewofj have signed this pacification inthe presence of two sixbscibing wgitnsses. 

